V5 docker-compose + traefik v2 url error

Hey there,

i am trying invoice ninja selfhosted and it looks amazing. To assess its feasability I installed it following the official guideline. I have a traefik setup allowing me to run it on my internal home network with proper DNS resolution. This works for everything, the tool works really good, until resources such as images or already generated PDFs are loaded. They get loaded from http://localhost/storage or similar url with localhost instead of http://domainname/storage- which makes little sense. It is strange because I can otherwise browse well through the application and everything seems to work with the correct domainname.
All I did was the usual adding labels to the docker container I want to make available (nginx in that example).

version: '3.7'

services:
  server:
    image: nginx
    restart: always
    container_name: invoiceninja_nginx
    volumes:
      - /media/docker-mounts/invoiceninja/config/nginx/in-vhost.conf:/etc/nginx/conf.d/in-vhost.conf:ro
      - /media/docker-mounts/invoiceninja/app/public:/var/www/app/public:ro
    depends_on:
      - invoiceninja-app
    networks:
      - external-net
    env_file: 
      - invoice.env
      - .env
    labels:
      - traefik.http.routers.invoices.rule=Host(`invoices.mylocaldomain.com`)
      - traefik.http.services.invoices.loadbalancer.server.port=80
    extra_hosts:
      - "in5.localhost:${GEARBOX_HOST_IP} " #host and ip

  invoiceninja-app:
    image: invoiceninja/invoiceninja:5
    container_name: invoiceninja_app
    restart: always
    env_file: 
      - invoice.env
      - .env
    volumes:
      - /media/docker-mounts/invoiceninja/config/hosts:/etc/hosts:ro
      - /media/docker-mounts/invoiceninja/app/public:/var/www/app/public:rw,delegated
      - /media/docker-mounts/invoiceninja/app/storage:/var/www/app/storage:rw,delegated
    depends_on:
      - invoiceninja_db
    networks:
      - external-net
    extra_hosts:
      - "in5.localhost:${GEARBOX_HOST_IP} " #host and ip

  invoiceninja_db:
    container_name: invoiceninja_database
    image: mariadb:10.4
    env_file: 
      - invoice.env
      - .env
    # ports:
    #   - "3305:3306"
    restart: always
    volumes:
      - /media/docker-mounts/invoiceninja/database:/var/lib/mysql:rw,delegated
    networks:
      - external-net
    extra_hosts:
      - "in5.localhost:${GEARBOX_HOST_IP} " #host and ip

networks:
  external-net:
    external: true

invoice.env:

# --- Invoice Ninja
IN_APP_URL=http://invoices.mylocaldomain.com
APP_KEY=base64:bM0123...
APP_DEBUG=false
REQUIRE_HTTPS=false
PHANTOMJS_PDF_GENERATION=false
PDF_GENERATOR=snappdf
QUEUE_CONNECTION=database
# DB connection
DB_HOST=invoiceninja_db
DB_PORT=3306
DB_DATABASE=ninja
DB_USERNAME=ninja
DB_PASSWORD=****
# Create initial user
# Default to these values if empty
# IN_USER_EMAIL=admin@example.com
# IN_PASSWORD=changeme!
IN_USER_EMAIL=
IN_PASSWORD=
# Mail options
MAIL_MAILER=log
MAIL_HOST=smtp.mailtrap.io
MAIL_PORT=2525
MAIL_USERNAME=null
MAIL_PASSWORD=null
MAIL_ENCRYPTION=null
MAIL_FROM_ADDRESS='user@example.com'
MAIL_FROM_NAME='Self Hosted User'
# MySQL
MYSQL_ROOT_PASSWORD=****
MYSQL_USER=ninja
MYSQL_PASSWORD=****
MYSQL_DATABASE=ninja

Ideas? It seems quite straight forward, but still strange.
Edit: Maybe to say if I take the request URL to a resource http://localhost/client/invoice/n68SvXVwCc6RWhfeO7dCNdq2iYBGWNLW/download?t=1634735414637&per_page=999999 and change the URL manually to http://invoices.mylocaldomain.com/client/invoice/n68SvXVwCc6RWhfeO7dCNdq2iYBGWNLW/download?t=1634735414637&per_page=999999 that works.

Maybe IN_APP_URL should be APP_URL?

Oh wow. That was easy. I had experimented before with having one global .env file for all my hosts and therefore prefixed. Didnt see this.
Thanks many times!!

Edit: Now when I add TLS/https to traefik it works, only the same urls as before only show with http instead of https
REQUIRE_HTTPS=true and TRUSTED_PROXIES="*" have no effect. Neither does LOCAL_DOWNLOAD=true

Ok, changing the APP_URL to https did the trick, together with TRUSTED_PROXIES=*

Would be interesting to know what kind of problems are potential introduced by giving a wildcard to trusted proxies.